Studies on the role of phospholipid tear supplements in dry eye disease

Abstract

Abstract

Aim The condition Dry eye disease (DED) can be caused by multiple pathological, physiological and environmental factors, which disturb the homeostasis of the ocular surface. Management of DED aims at restoration of the tear film and ocular surface homeostasis. The study aimed to evaluate the effectiveness of phospholipid tear supplements in the treatment of DED and microbial keratitis, the latter of which has a higher prevalence among DED patients. To facilitate these studies a number of techniques were developed to assess the tear film.

Methods An extensive array of objective and subjective tests were used in the current work. New techniques were developed and validated, such as the SMTube to assess tear production and a multiplex immunoassay to assess tear inflammatory biomarkers. These studies were designed to investigate the role of phospholipids in the tear film of subjects with dry eye, and in the healing-process associated with microbial keratitis.

Results It was found that phospholipid-based supplement and comparable lipid-based supplements provided symptomatic relief in mild–to-moderate DED patients in a two weeks’ study. However, this was not supported with improvements in objective signs. In another one-month study comparing the phospholipid tear supplement to an aqueous-based supplement, it was found that phospholipid tear supplements improved tear film stability, accompanied with symptomatic relief. Moreover, the phospholipid tear supplement caused a reduction in the concentration of some of the inflammatory biomarkers. This was not observed with the aqueous tear supplement. Based on a clinical grading study of bacterial keratitis in an animal model, the phospholipid supplement had favourable outcomes, possibly due to enhancement of delivery of the antibiotic.

Conclusion Phospholipid tear supplements used as a first-line of treatment for mild-to-moderate DED can improve the likely prognosis through improving tear film stability and reducing inflammation. It is clear from these studies that measuring the inflammatory milieu, in addition to signs and symptoms of DED, is essential if a therapeutic agent is to be assessed for this condition’s treatment.